The lowly work of self-affirmation ballooned to outrageous proportions in the goth-pop phantasmagoria that Lady Gaga brought to Staples Center on Sunday night.

Playing the first of two concerts at the downtown arena, the singer appointed herself ambassador for the maligned and the misunderstood, promising liberation to those willing to flout orthodoxy -- or, as she put it not long into the 2 ½-hour show, “a freedom so magnificent we’ll make all of California explode.”

It was typically high-flown talk from an outspoken superstar who nonetheless finds herself a little closer to earth these days.

Unlike her last visit to Staples, in 2011, Sunday’s gig didn’t feel packed to the rafters. (At press time, tickets for Monday’s show were still available). And she seems to have ceded her once-untouchable place in the tabloid press to Rihanna.

But if she’s taken a hit, Lady Gaga isn’t lying down: That the Golden State stood intact early Monday hardly reflected a lack of determination to follow through on her threat.

The Born This Way Ball, named after her most recent album, spared no extravagance as it moved from spectacle to spectacle, each set piece playing out against a detailed reproduction of a multi-level medieval castle.

During “Born This Way” she literalized the song’s lyric, emerging through a narrow passageway between the fishnet-stocking-wrapped legs of an enormous blow-up doll. In “Bloody Mary” the singer and two lookalikes coasted around a circular runway on apparently remote-controlled platforms while a succession of men wearing miniskirts paraded behind them.

And for “Poker Face” Lady Gaga donned a version of the notorious meat dress she wore to the 2010 MTV Video Music Awards. Then she supersized the raw-beef factor, sprawling out on what can only be described as a meat sofa.

It was enough to make the holographic face that delivered “Paparazzi” from inside a floating diamond seem lackluster by comparison. (At least one component -- a black bra equipped with miniature machine guns -- seemed Sunday to have been removed from the show after its appearance this month at a tour stop in Vancouver caused an outcry.)

Yet Lady Gaga, who reportedly is set to play a private inaugural event for Obama campaign staffers Tuesday, took pains to endow the whiz-bang production with a scrappier human element -- a sign, perhaps, that she sees a limit to the more-is-more approach.

In several lengthy addresses to the audience she spoke frankly about her struggle to break into show business, saying that as recently as five years ago she was working as a waitress and a coat-check girl and that she’d eventually turned to stripping when money got tight.

“You really shouldn’t judge people” who decide to strip, she added, before describing herself as “essentially just one of the highest-paid strippers in the world.”

Throughout Sunday’s performance -- rapturously received by the fans she calls “little monsters” -- Lady Gaga’s powerful singing demonstrated, too, that there’s a person inside the overwhelming “everything” she declared she could be in “Government Hooker.”

In “Bad Romance” she dug into the song’s wordless whoa-oh-ohs with full-lunged bravado and equaled Beyonce’s recorded vocals in a rendition of their throbbing 2009 duet, “Telephone.”

Later, during her encore, Lady Gaga repurposed two of the most anthemic numbers from “Born This Way” -- “Marry the Night” and “The Edge of Glory” -- as plaintive piano ballads, jettisoning each song’s beat in order to elongate their top-line melodies. Both thrilled in spite of the downgrade in energy.

The strong singing helped pull together music that roamed as freely as the show’s onstage action. There were grinding disco-punk riffs in “Judas,” fluttering Latin rhythms in “Americano” and the tinny synth-pop entreaties of “Just Dance,” the debut single that Lady Gaga said changed her life.

Midway through the concert she took up the sound -- and the signifiers -- of mid-’80s rock 'n' roll with “Hair” and “Electric Chapel,” for which she strapped on a guitar and played along with the two guitarists in her five-piece band. And though “Heavy Metal Lover” actually eschewed heavy metal in favor of a sleek house groove, Lady Gaga nailed the look with a black-leather get-up that made her resemble the seat of the motorcycle she was riding. (The female dancer sitting on top of her contributed to the illusion.)

Did it all cohere entirely? Of course not. A narrative about Lady Gaga’s being a visitor from an alien civilization -- something that may have had to do with an upcoming album she’s said will be titled “ARTPOP” -- seemed especially half-baked, dropped as it more or less was an hour into the show.

But at Staples Center the singer used incoherence and contradiction as a kind of weapon against the institutionalized irrationality she perceives in the discrimination she sings about. “Tonight it doesn’t matter if we have different views,” she said following the childbirth sequence in “Born This Way,” in which she aligns herself with a laundry list of demographic groups. “I’m not a prisoner — they will not define me.”

And, anyway, since when do we demand organized thought from our pop stars? Shouldn’t a meat sofa be sufficient?